TWI731774B - Polyimide polymer, polyimide mixture and polyimide film - Google Patents

Abstract

The present disclosure provides a polyimide polymer. The polyimide polymer includes a repeating unit represented by formula (I), in which each symbol is as defined in the specification. Accordingly, by introducing a large chemically reactive group on the molecular chain of the polyimide polymer, the processing and applicability of the polymer can be improved and applied to an electronic element or 5G industry.

Description

Polyimide polymer, polyimine mixture and polyimide film prepared therefrom

The present invention relates to a polyimide polymer, a polyimide mixture and a polyimide film prepared therefrom, in particular to a reactive polyimide polymer, a polyimide mixture and the polyimide film prepared therefrom. The prepared polyimide film.

Nowadays, polymers have been widely used in the semiconductor industry, automobile industry, optoelectronic industry, biomedical materials, and communication materials. Therefore, in the polymer field, there is an increasing need for functional polymers with higher physical properties, such as Properties such as heat resistance, chemical resistance, plasticity, low dielectric constant or low dielectric loss.

Traditionally, polyimine is formed by polymerizing diamine compound and bisacid anhydride compound to form polyimide, which is processed by solution method and then formed into polyimide in situ by thermal cyclization reaction; on the other hand, it is also Polyimide can be reacted to polyimide by chemical cyclization, but limited by molecular design and chemical reaction, there are few polyimide polymer chains with chemically reactive huge groups.

In view of this, how to develop a novel polyimide polymer and improve the polymer structure to obtain high-performance polymer materials and improve its applicability.

One of the objects of the present invention is to provide a polyimide polymer, which is achieved by introducing a chemically reactive huge group on the polyimide polymer chain, so that it has the characteristics of post-crosslinking, post-functionalization reaction, etc. .

Another object of the present invention is to provide a polyimide mixture and a polyimide film prepared therefrom, which can be processed through a polyimide polymer containing a Mildren’s acid group that can be dissolved in an organic solvent. The polyimide film has high transparency in the visible light region.

式(I)， 其中R ₁及R ₂彼此相同或不同，且各自獨立為醚基、酯基、胺基或其他雜原子鏈段、烷基、烯基、炔基、芳基或其他純碳鏈段，Ar為含芳香環之四價有機基團。 One embodiment of the present invention is to provide a polyimide polymer having a repeating unit as shown in formula (I):

Formula (I), Wherein R ₁ and R ₂ are the same or different from each other, and are each independently an ether group, an ester group, an amine group or other heteroatom segments, alkyl groups, alkenyl groups, alkynyl groups, aryl groups or other pure carbon segments, and Ar is Tetravalent organic group containing aromatic ring.

According to the polyimide polymer of the foregoing embodiment, in formula (I), R ₁ and R ₂ may be benzyl groups.

式(i)、 式(ii)、 式(iii)。 According to the polyimide polymer of the foregoing embodiment, in formula (I), Ar can be one of the structures shown in formula (i), formula (ii) or formula (iii):

Formula (i), Formula (ii), Formula (iii).

式(I)， 其中R ₁及R ₂彼此相同或不同，且各自獨立為醚基、酯基、胺基或其他雜原子鏈段、烷基、烯基、炔基、芳基或其他純碳鏈段，Ar為含芳香環之四價有機基團。含二氧化矽溶液係於一第二有機溶劑中分散二氧化矽粒子，且以聚醯亞胺高分子與二氧化矽粒子的總重量計，所述二氧化矽粒子的含量為大於0重量百分比且小於或等於40重量百分比。 Another embodiment of the present invention is to provide a polyimide mixture comprising a polyimide precursor and a solution containing silicon dioxide. The polyimide precursor is a polyimide polymer dissolved in a first organic solvent, and the polyimide polymer has a repeating unit as shown in formula (I):

Formula (I), Wherein R ₁ and R ₂ are the same or different from each other, and are each independently an ether group, an ester group, an amine group or other heteroatom segments, alkyl groups, alkenyl groups, alkynyl groups, aryl groups or other pure carbon segments, and Ar is Tetravalent organic group containing aromatic ring. The silica-containing solution is to disperse silica particles in a second organic solvent, and the content of the silica particles is greater than 0 weight percent based on the total weight of the polyimide polymer and the silica particles And less than or equal to 40 weight percent.

According to the polyimide mixture of the foregoing embodiment, in formula (I), R ₁ and R ₂ may be benzyl groups.

式(i)、 式(ii)、 式(iii)。 According to the polyimide mixture of the foregoing embodiment, in formula (I), Ar can be one of the structures shown in formula (i), formula (ii) or formula (iii):

Formula (i), Formula (ii), Formula (iii).

According to the polyimide mixture of the foregoing embodiment, the first organic solvent may be N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone or N ,N-Diethylacetamide.

According to the polyimide mixture of the foregoing embodiment, the second organic solvent can be selected from alcohols, ketones, ethers, esters or mixtures thereof.

Another embodiment of the present invention is to provide a polyimide film, which is obtained by coating the aforementioned polyimide mixture on a substrate and calcining it.

According to the polyimide film of the foregoing embodiment, the yellowness (YI) of the polyimide film may be 6.0 or less.

Thereby, the polyimide polymer of the present invention introduces chemically reactive groups to make it have the characteristics of post-crosslinking, post-functionalization reaction, etc., and has high transparency in the visible light region, and can be used in flexible printed circuits. The application field of board and colorless and transparent polyimide.

The various embodiments of the present invention will be discussed in more detail below. However, this embodiment may be an application of various inventive concepts, and may be implemented in various specific ranges. The specific implementation is for illustrative purposes only, and is not limited to the scope of disclosure.

In the present invention, a skeleton formula is sometimes used to express the structure of a compound, and such a notation may omit carbon atoms, hydrogen atoms, and carbon-hydrogen bonds. If functional groups are clearly drawn in the structural formula, the drawn ones shall prevail.

In the present invention, "polyimide polymer has a structure as shown in formula (I)". In order to be concise and clear, it is sometimes expressed as polyimide polymer shown in formula (I) or The expression of polyimide polymer (I) and other compounds or groups can be deduced by analogy.

In the present invention, if it is not specifically specified whether a certain group is substituted, the group may represent a substituted or unsubstituted group. For example, "alkyl" may refer to substituted or unsubstituted alkyl.

＜Polyimide polymer＞

式(I)， 其中R ₁及R ₂彼此相同或不同，且各自獨立為醚基、酯基、胺基或其他雜原子鏈段、烷基、烯基、炔基、芳基或其他純碳鏈段，Ar為含芳香環之四價有機基團。 The present invention provides a polyimide polymer having one of the repeating units shown in formula (I):

Formula (I), Wherein R ₁ and R ₂ are the same or different from each other, and are each independently an ether group, an ester group, an amine group or other heteroatom segments, alkyl groups, alkenyl groups, alkynyl groups, aryl groups or other pure carbon segments, and Ar is Tetravalent organic group containing aromatic ring.

With the above structure, the polyimide polymer of the present invention uses Meldrum's Acid as the reactive group, which makes the polyimide polymer chemically reactive and can be dissolved in organic solvents for processing . In addition, Michler’s acid can undergo a thermal cracking reaction at high temperatures to generate ketene groups, which can then undergo subsequent reactions and self-crosslinking reactions.

式(I-1)，

式(I-2)，

式(I-3)，

式(I-4)，

式(I-5)。 In detail, after the polyimide polymer (I) of the present invention is heated, Michler’s acid will generate an enone group, which is a repeating unit represented by formula (I-1), which can then undergo self-crosslinking reaction. , As one of the repeating units shown in formula (I-2), or react with other functional groups such as amine groups, alcohol groups or isocyanate groups, as shown in formula (I-3), formula (I-4) or A repeating unit represented by formula (I-5), where R'is a specific functional group, it can be seen that the polyimide polymer of the present invention has chemical reactivity.

Formula (I-1),

Formula (I-2),

Formula (I-3),

Formula (I-4),

Formula (I-5).

式(i)、 式(ii)、 式(iii)。 詳細來說，當式(I)中，R ₁及R ₂為苄基，Ar為式(i)所示之結構時，其具有如式(I-AA)所示之一結構：

式(I-AA)。 According to the aforementioned polyimide polymer (I), R ₁ and R ₂ can be but not limited to benzyl, and Ar can be, but not limited to, as shown in formula (i), formula (ii) or formula (iii) One structure:

Formula (i), Formula (ii), Formula (iii). _{In detail, when R 1} and R ₂ are benzyl groups in formula (I), and Ar is the structure shown in formula (i), it has a structure shown in formula (I-AA):

Formula (I-AA).

＜Preparation method of polyimide polymer＞

With reference to Fig. 1, it is a flow chart of a method 100 for preparing a polyimide polymer according to an embodiment of the present invention. In detail, the preparation method 100 of the polyimide polymer of the present invention is prepared by a chemical cyclization method. In Figure 1, the preparation method 100 of the polyimide polymer includes step 110, step 120, and step 130 and step 140.

式(A)， 其中R ₁及R ₂彼此相同或不同，且各自獨立為醚基、酯基、胺基或其他雜原子鏈段、烷基、烯基、炔基、芳基或其他純碳鏈段。 Step 110 is to provide a diamine compound, which has a structure as shown in formula (A):

Formula (A), Wherein R ₁ and R ₂ are the same or different from each other, and are each independently an ether group, an ester group, an amine group or other heteroatom segment, an alkyl group, an alkenyl group, alkynyl group, an aryl group or other pure carbon segments.

Step 120 is a dissolving step, which is to dissolve the diamine compound (A) in an organic solvent to form a first mixture. Specifically, the organic solvent may be, but not limited to, N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF) , N-methyl-2-pyrrolidone (NMP) or N,N-diethylacetamide and other amide-based solvents, the above organic solvents can be used alone or in combination.

Step 130 is to provide a dianhydride monomer, which is to form a polyamic acid solution (PAA) after mixing the dianhydride monomer and the first mixture. In detail, the dianhydride monomer can be, but is not limited to, a tetracarboxylic dianhydride containing an aromatic ring. A specific example is 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) , 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride ( BPDA) or 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride (ODPA).

Step 140 is to perform an imidization reaction, which is to add a dehydrating agent and an imidizing agent to the polyimide solution, and heat to react to form the polyimide polymer (I). Specifically, the dehydrating agent may be, but not limited to, acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, or trifluoroacetic acid, and the imidizing agent may be, but not limited to, pyridine, picoline, quinoline or isocyanide. quinoline.

Specifically, taking polyimide polymer (I-AA) as an example, the reaction process is shown in Table 1 below, wherein the diamine compound represented by formula (A-1) is in formula (A), R ₁ and R ₂ is the structure of benzyl. Table I

＜Polyimide mixture＞

式(I)， 其中R ₁及R ₂彼此相同或不同，且各自獨立為醚基、酯基、胺基或其他雜原子鏈段、烷基、烯基、炔基、芳基或其他純碳鏈段，Ar為含芳香環之四價有機基團，且所述第一有機溶劑可為但不限於N,N-二甲基乙醯胺、N,N-二甲基甲醯胺、N-甲基-2-吡咯烷酮或N,N-二乙基乙醯胺等醯胺系溶劑，並可單獨使用或混合多種使用。關於聚醯亞胺高分子(I)請參考上文，在此不另贅述。 The present invention provides a polyimide mixture, which comprises a polyimide precursor and a solution containing silicon dioxide. In detail, the polyimide precursor is a polyimide polymer dissolved in a first organic solvent, and the polyimide polymer has a repeating unit as shown in formula (I):

Formula (I), Wherein R ₁ and R ₂ are the same or different from each other, and are each independently an ether group, an ester group, an amine group or other heteroatom segments, alkyl groups, alkenyl groups, alkynyl groups, aryl groups or other pure carbon segments, and Ar is A tetravalent organic group containing an aromatic ring, and the first organic solvent may be, but not limited to, N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2 -Amine-based solvents such as pyrrolidone or N,N-diethylacetamide, which can be used alone or in combination. Regarding the polyimide polymer (I), please refer to the above, and will not be repeated here.

In the present invention, the polyimide mixture is a mixture of the aforementioned polyimide precursor and a silica-containing solution, wherein the silica-containing solution is dispersed in a second organic solvent to disperse silica particles and polymerized Based on the total weight of the imine polymer and the silica particles, the content of the silica particles is greater than 0 weight percent and less than or equal to 40 weight percent. The second organic solvent of the present invention is selected from alcohols, ketones, ethers, esters, or mixtures thereof. Preferably, the second organic solvent can be, but not limited to, methyl isobutyl ketone (methyl isobutyl ketone, MIBK). ).

＜Polyimide film＞

式(II)， 其中R ₁及R ₂彼此相同或不同，且各自獨立為醚基、酯基、胺基或其他雜原子鏈段、烷基、烯基、炔基、芳基或其他純碳鏈段，x大於0且小於1，Ar為含芳香環之四價有機基團，如式(i)、式(ii)或式(iii)所示之一結構：

式(i)、 式(ii)、 式(iii)。 The present invention provides a polyimide film, which is obtained by coating the aforementioned polyimide mixture on a substrate and then calcining it. In the present invention, the polyimide film is obtained by blending silicon dioxide in the polyimide film. Among the imine polymers, it has a structure as shown in formula (II):

Formula (II), Wherein R ₁ and R ₂ are the same or different from each other, and are each independently an ether group, ester group, amine group or other heteroatom segment, alkyl group, alkenyl group, alkynyl group, aryl group or other pure carbon segment, x is greater than 0 and less than 1, Ar is a tetravalent organic group containing an aromatic ring, such as one of the structures shown in formula (i), formula (ii) or formula (iii):

Formula (i), Formula (ii), Formula (iii).

In detail, the coating method of the polyimide mixture can be, but is not limited to, a knife coating method, a spin coating method, a roller coating method, a slit coating method, and other known coating methods, and the substrate can be But it is not limited to suitable substrates such as fabric, copper foil, plastic, and glass.

The following specific examples are used to further illustrate the present invention, so as to facilitate those skilled in the art to which the present invention pertains to fully utilize and practice the present invention without excessive interpretation. These embodiments should not be regarded as It limits the scope of the present invention, but is used to illustrate how to implement the materials and methods of the present invention.

<Example>

Example 1 of the present invention is a polyimide polymer (I-AA), and its synthesis method is to put 3 grams (8.465 mmole) of diamine compound (A-1) and 35 mL of dry NMP into 100 mL of In the double-necked round-bottom flask, the inlet of the double-necked round-bottomed flask is equipped with a condenser and the outlet is equipped with nitrogen, and it is placed on a magnetic stirrer and ^{stirred at 25 o} C until completely dissolved. Then 3.76 g (8.465 mmole) of 4,4'-(hexafluoroisopropyl)diphthalic anhydride (6FDA) was added in batches and reacted at room temperature for 24 hours to form polyamide acid. Then, 4.32 g (42.325 mmole) of acetic anhydride (AcO ₂ ) and 3.348 g (43.325 mmole) of pyridine were added for the imidization reaction, and then stirred at room temperature for 2 hours, and then under nitrogen Under the environment, ^{heat it in an oil bath at 100 o} C for 5 hours. After cooling, pour it into 1 L of methanol, stir constantly to produce a precipitate, and collect the precipitate by filtration and dry it under vacuum to obtain Polyimide polymer (I-AA).

Example 1 was subjected to FTIR analysis, ¹ H-NMR analysis, ¹³ C-NMR analysis, and ¹⁹ F-NMR analysis to confirm the structure of Example 1. Please with reference to FIG. 2A, FIG. 2B, 2C and FIG and FIG. 2D, wherein FIG. 2A line shows Example 1 and Comparative Example FTIR spectrum of FIG. 1, FIG. 2B line shows Example 1 The ¹ H -NMR spectrogram, Figure 2C shows the ¹³ C-NMR spectrum of ^{Example 1, and Figure 2D shows the 19} F-NMR spectrum of Example 1. From the results of Figure 2A to Figure 2D, it can be confirmed that the product of Example 1 is a polyimide polymer (I-AA), and Comparative Example 1 is a diamine compound (A-1).

The preparation method of the polyimide film of Example 2 to Example 4 of the present invention is to first dissolve 1 g of the polyimide polymer (I-AA) of Example 1 in 5.6 mL of NMP solvent, and then add Containing silica solution to form a polyimide mixture. Then use a 200 μm spatula to cast on a glass plate, heat it to 120 ^o C in a vacuum oven for 3 hours, and then ^{heat it at 180 o} C, 200 ^o C, 240 ^o C and 280 ^o C for 1 hour, and then Heating at 300 ^o C for 30 minutes, the polyimide film of Example 2 to Example 4 can be obtained. The difference between Example 2 and Example 4 is that the amount of silica particles added is different. Based on the total weight of the polyimide polymer and silica particles, the amount of silica particles added in Example 2 is 20. wt%, the addition amount of silica particles in Example 3 is 30 wt%, and the addition amount of silica particles in Example 4 is 40 wt%.

Examples 2 to 4 were subjected to ATR-FTIR analysis and XRD analysis to confirm the structures of Examples 2 to 4. Please refer to Figures 3 and 4 together. Figure 3 shows the ATR-FTIR spectra of Examples 1 to 4 and Comparative Example 2, and Figure 4 shows the ATR-FTIR spectra of Examples 1 to 4 and Comparative Example. 2 to Comparative Example 3 XRD diffraction analysis graphs, where Comparative Example 2 is the thin film of Example 1 after heating, and Comparative Example 3 is silicon dioxide.

First, from the results in Figure 3, it can be observed that the characteristic peak (1337 cm ^-1 ) of the Michler's acid lactone structure in Examples 2 to 4 and Comparative Example 2 has disappeared, which proves the ring-opening reaction of Michler's acid Occurs, and from the analysis results of Example 2 to Example 4, the changes caused by the reaction of Michler’s acid and silicon dioxide can be observed. The newly formed CO stretching (1250 cm ^-1 , 1050 cm ^-1 ) can prove that the alkene The nucleophilic addition reaction between the ketone group and the hydroxyl group proceeds. In addition, in Example 2 to Example 4, in addition to the imide ring (741 cm ^-1 ), CN stretching (1364 cm ^-1 ), and C=O asymmetrical and symmetrical stretching (1779 cm ^-1 , 1724 cm ^{-1 ), the imide structure can be observed. 1} ) In addition to the characteristic peaks, the Si-O-Si structural characteristics (1100 cm ^-1 ) of silicon dioxide can still be observed. It is confirmed that the products of Examples 2 to 4 are polysilicon doped with silicon dioxide. Amine film.

計算而得，薄膜展示最大的繞射峰值2θ約為13.43 ^o~13.79 ^o，計算所得d-spacing約為6.59 Å~6.42 Å，此數值說明了此類聚醯亞胺薄膜材料展現比於芳香族Kapton(d=3 Å)兩倍多的分子鏈間距。此外，比較例3的繞射值約為22.08 ^o，d-spacing約為4.03 Å，而實施例2至實施例4於此區間中皆無明顯地繞射峰值出現，證明二氧化矽粒子均勻分散於分子鏈段間，且透過比較例2與實施例2至實施例4之d-spacing差異，可說明了二氧化矽的加入確實可於分子鏈段架構出較大的空間以提升材料的自由體積，其中實施例1至實施例4以及比較例2至比較例3的繞射角度(2θ)以及分子鏈間距(d)的量測結果如下表二所示。 表二   2θ(degree) d(Å) 實施例1 13.43 6.59 實施例2 13.66 6.48 實施例3 13.51 6.55 實施例4 13.55 6.53 比較例2 13.79 6.42 比較例3 22.08 4.03 In addition, according to the broad peak (2θ=9 ^o ~24 ^o ) shown in Figure 4, it can be seen that the prepared polyimide films are all amorphous, and the molecular chain spacing (d-spacing) can be passed through Bragg's equation:

It is calculated that the maximum diffraction peak 2θ displayed by the film is about 13.43 ^o ~13.79 ^o , and the calculated d-spacing is about 6.59 Å~6.42 Å. This value shows that this type of polyimide film material exhibits better performance than the aromatic Kapton (d=3 Å) more than twice the molecular chain spacing. In addition, the diffraction value of Comparative Example 3 is about 22.08 ^o , d-spacing is about 4.03 Å, and there is no obvious diffraction peak in the range of Examples 2 to 4, which proves that the silicon dioxide particles are uniformly dispersed in The difference between molecular segments and the d-spacing difference between Comparative Example 2 and Examples 2 to 4 shows that the addition of silicon dioxide can indeed create a larger space in the molecular segment to increase the free volume of the material. Among them, the measurement results of the diffraction angle (2θ) and the molecular chain distance (d) of Examples 1 to 4 and Comparative Example 2 to Comparative Example 3 are shown in Table 2 below. Table II 2θ(degree) d(Å) Example 1 13.43 6.59 Example 2 13.66 6.48 Example 3 13.51 6.55 Example 4 13.55 6.53 Comparative example 2 13.79 6.42 Comparative example 3 22.08 4.03

＜Thermal quality test＞

Examples 1 to 4 and Comparative Example 2 were evaluated for thermal properties. The thermal property evaluation methods include thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA).

Please refer to Figure 5A, Figure 5B and Figure 5C, where Figure 5A shows the TGA analysis diagram of Example 1 and Comparative Example 2, and Figure 5B shows Example 2 to Example 4 and Comparative Example 2 in nitrogen The TGA analysis diagram below, Figure 5C shows the TGA analysis diagrams of Examples 2 to 4 and Comparative Example 2 under air.

According to the TGA analysis, the thermal cracking temperature (T _d ) of Examples 1 to 4 and Comparative Example 2 can be obtained, and the measurement results are shown in Table 3 below. Table Three T _d ( ^o C) Nitrogen air Example 1 235 - Example 2 437 447 Example 3 427 423 Example 4 433 440 Comparative example 2 439 430

Please refer to Fig. 6A, Fig. 6B, Fig. 6C and Fig. 6D. Fig. 6A shows the DMA analysis chart of Comparative Example 2, Fig. 6B shows the DMA analysis chart of Example 2, and Fig. 6C shows The DMA analysis chart of Example 3, and FIG. 6D shows the DMA analysis chart of Example 4.

2 that may be analyzed by DMA to the glass transition temperature ^(o C) Example 4 and Comparative Example 2, and a storage modulus at 50 ^o C embodiment, the measurement results thereof are shown in Table IV. Table Four T _g ( ^o C) Storage modulus (MPa) Example 2 298 5212 Example 3 275 6013 Example 4 279 6564 Comparative example 2 303 4358

＜Mechanical quality measurement＞

The tensile strength of Examples 1 to 4 and Comparative Example 2 were analyzed to measure their mechanical properties. Please refer to Figure 7, which shows the stress and strain diagrams of Examples 1 to 4 and Comparative Example 2. . From the tensile strength analysis, the stress, strain, and Young's modulus of Examples 1 to 4 and Comparative Example 2 can be obtained. The measurement results are shown in Table 5 below. Table 5 Stress (MPa) strain(%) Young's modulus (MPa) Example 1 70.92±3.65 9.81±0.36 1871.9±38.1 Example 2 82.71±1.06 3.86±0.13 3647.6±44.9 Example 3 70.19±1.54 2.52±0.05 3483.9±58.2 Example 4 72.67±2.72 3.26±0.11 3194.6±62.0 Comparative example 2 91.49±2.10 5.41±0.25 2467.2±83.3

＜Optical quality measurement＞

Perform UV spectrum analysis of Examples 1 to 4 and Comparative Example 2, and please refer to Figures 8 and 9, where Figure 8 shows the UV analysis diagrams of Examples 1 to 4 and Comparative Example 2. FIG. 9 is a schematic diagram of the films of Examples 1 to 4 and Comparative Example 2. FIG. The UV analysis shows the light transmittance (T _λ ) and cutoff wavelength (λ) of Examples 1 to 4 and Comparative Example 2. The measurement results are shown in Table 6 below. Table 6 T ₄₀₀ (%) T ₄₅₀ (%) T ₅₀₀ (%) λ (nm) Example 1 69.9 84.7 87.0 319 Example 2 43.8 80.4 85.9 353 Example 3 65.3 86.6 88.9 323 Example 4 60.4 84.9 88.0 328 Comparative example 2 44.0 78.5 84.9 350

In addition, the refractive index, dielectric constant and color parameters of Examples 1 to 4 and Comparative Example 2 were measured. The measurement results of refractive index (RI) and dielectric constant (ε) are shown in Table 7 below. The measurement results of color parameters including lightness (L*), red-greenness (a*), yellow-blueness (b*), yellowness (YI) and haze (HAZE) are shown in Table 8 below. Table Seven Refractive Index (RI) Dielectric constant (ε) Example 1 1.57 2.71 Example 2 1.56 2.68 Example 3 1.53 2.61 Example 4 1.54 2.71 Comparative example 2 1.59 2.78 Table 8 L* a* b* YI HAZE Example 1 95.28 -0.74 2.99 5.08 0.71 Example 2 94.73 -1.10 5.43 9.36 0.92 Example 3 95.66 -0.38 2.84 5.01 0.86 Example 4 95.13 -1.12 5.59 9.59 0.74 Comparative example 2 95.01 -1.17 4.97 8.44 1.64

From the above analysis results of thermal, mechanical and optical properties, it can be seen that the polyimide film doped with silicon dioxide of the present invention has thermal stability, stronger mechanical strength and higher mechanical strength than the polyimide film doped with silicon dioxide. The characteristic of high light transmittance, and the yellowness (YI) of Example 3 is below 6.0, which has high transparency in the visible light region.

In summary, the polyimide polymer of the present invention introduces chemically reactive groups to make it have the characteristics of post-crosslinking and post-functionalization reaction, and the polyimide polymer prepared after being modified with silica In addition to the characteristics of thermal stability, strong mechanical strength and high light transmittance, imine film also has high transparency in the visible light region, making it applicable to the field of flexible printed circuit boards and colorless and transparent polyimide.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone familiar with the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection of the present invention The scope shall be subject to the definition of the attached patent application scope.

100: Preparation method of polyimide polymer 110, 120, 130, 140: steps

In order to make the above and other objects, features, advantages and embodiments of the present invention more comprehensible, the description of the accompanying drawings is as follows: Figure 1 is a polyimide polymer according to one embodiment of the present invention Step flow chart of the preparation method; Figure 2A shows the FTIR spectra of Example 1 and Comparative Example 1; Figure 2B shows the ¹ H-NMR spectrum of Example 1; Figure 2C shows the Example The ¹³ C-NMR spectrum of 1; The 2D diagram shows the ¹⁹ F-NMR spectrum of Example 1; The third diagram shows the ATR-FTIR spectrum of Examples 1 to 4 and Comparative Example 2; Fig. 4 shows the XRD diffraction analysis graphs of Example 1 to Example 4 and Comparative Example 2 to Comparative Example 3; Fig. 5A shows the TGA analysis graph of Example 1 and Comparative Example 2; Fig. 5B Shows the TGA analysis diagrams of Examples 2 to 4 and Comparative Example 2 under nitrogen; Figure 5C shows the TGA analysis diagrams of Examples 2 to 4 and Comparative Example 2 under air; Figure 6A is Figure 6B shows the DMA analysis diagram of Example 2; Figure 6C shows the DMA analysis diagram of Example 3; Figure 6D shows the DMA analysis diagram of Example 4 Figures; Figure 7 shows the stress and strain diagrams of Examples 1 to 4 and Comparative Example 2; Figure 8 shows the UV analysis diagrams of Examples 1 to 4 and Comparative Example 2; and Figure 9 The schematic diagrams of the films of Examples 1 to 4 and Comparative Example 2 are shown.

Claims (10)

A polyimide polymer having one of the repeating units shown in formula (I):

Wherein R ₁ and R ₂ are the same or different from each other, and are each independently an ether group, an ester group, an amino group, an alkyl group, an alkenyl group, an alkynyl group, or an aryl group, and Ar is a tetravalent organic group containing an aromatic ring. The polyimide polymer according to claim 1, wherein in the formula (I), the _{structures of the R 1} and the R ₂ are as follows:

The polyimide polymer according to claim 1, wherein in the formula (I), the Ar is one of the structures represented by the formula (i), the formula (ii) or the formula (iii):

Formula (i), Formula (ii), Formula (iii). A polyimide mixture, comprising: a polyimine precursor, which is a polyimine polymer dissolved in a first organic solvent, and the polyimine polymer has the formula (I) Show one of the repeating units:

Wherein R ₁ and R ₂ are the same or different from each other, and are each independently an ether group, an ester group, an amino group, an alkyl group, an alkenyl group, an alkynyl group, or an aryl group, and Ar is a tetravalent organic group containing an aromatic ring; and one Silica-containing solution, which is to disperse silica particles in a second organic solvent, and based on the total weight of the polyimide polymer and the silica particles, the content of the silica particles is greater than 0 weight percent and less than or equal to 40 weight percent. The polyimide mixture according to claim 4, wherein in the formula (I), the _{structures of the R 1} and the R ₂ are as follows:

The polyimide mixture according to claim 4, wherein in the formula (I), the Ar is one of the structures represented by the formula (i), the formula (ii) or the formula (iii):

The polyimide mixture according to claim 4, wherein the first organic solvent is N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone Or N,N-diethylacetamide. The polyimide mixture according to claim 4, wherein the second organic solvent is selected from alcohols, ketones, ethers, esters or mixtures thereof. A polyimide film, which is obtained by coating the polyimide mixture described in any one of claims 4 to 8 on a substrate and calcining. The polyimide film according to claim 9, wherein the yellowness (YI) of the polyimide film is 6.0 or less.

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